Patent US4298088A successfully refreshed from Google Patents.
US4298088A
Expired / Lapsed
US
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Diffuser resonances
Assignee: BBC BROWN BOVERI and Co Ltd
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Filing: 1979-06-08
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Granted: 1981-11-03
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Expires: 1999-06-08
Abstract
Abstract For suppression of flow-driven resonances, a cross section modification is undertaken at the outlet of a diffuser. The length of the cross section modification stands in a specified relationship to the sonic wave to be suppressed.
Inventors
- 👤 Jakob Keller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:03
CPC Classifications
F; F15; F15D; F15D1/00; F15D1/08; B; B05; B05B; B05B15/00; F01; F01D; F01D17/00; F01D17/10; F01D17/12; F01D17/14; F01D17/141; F01D17/145
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
81 words
A diffuser structure comprising: a flow path having an inlet and an outlet, the inlet having a cross-sectional flow area which is less than the cross-sectional flow area of the outlet; a flow-driven resonance positioned immediately upstream of the flow path inlet; means for modifying the acoustic impedance of the flow path, positioned at the flow path outlet but upstream thereof, including an abrupt change in the cross-sectional flow area of the flow path, and operable to suppress the flow-driven resonance.
Claim 2
Dependent Claim
81 words
A diffuser structure comprising: a flow path having an inlet and an outlet, the inlet having a cross-sectional flow area which is less than the cross-sectional flow area of the outlet; a flow-driven resonance positioned immediately upstream of the flow path inlet; means for modifying the acoustic impedance of the flow path, positioned at the flow path outlet but upstream thereof, including an abrupt change in the cross-sectional flow area of the flow path, and operable to suppress the flow-driven resonance.
Claim 3
Dependent Claim
28 words
The diffuser structure of claim 1 wherein the abrupt change of cross section of the flow path outlet is symmetrical about an axis of the flow path outlet.
Claim 4
Dependent Claim
28 words
The diffuser structure of claim 1 wherein the abrupt change of cross section of the flow path outlet is asymmetrical over a circumference of the flow path outlet.
Claim 5
Dependent Claim
33 words
The diffuser structure of claims 2 or 3 wherein the flow path outlet with an abrupt change of cross section has the form of a cavity extending over the circumference of the outlet.
Claim 6
Dependent Claim
31 words
The diffuser structure of claims 2 or 3 wherein the flow path outlet with an abrupt change of cross section provides a contraction of a cross sectional area of the outlet.
Claim 7
Dependent Claim
24 words
The diffuser structure of claim 5 wherein a member is provided at an outside circumference of the flow path outlet to provide said contraction.
Claim 8
Dependent Claim
33 words
The diffuser structure of claims 2 or 3 wherein the abrupt change of cross section of the flow path outlet is provided by a radial deflection of walls at the flow path outlet.
Claim 9
Dependent Claim
32 words
The diffuser structure of claim 7 wherein the radial deflection of the walls in the flow path outlet is provided by a ring-shaped insert arranged on an inside circumference of the outlet.
Claim 10
Dependent Claim
29 words
The diffuser structure of claim 7 wherein the flow path inlet is arranged within a valve, said valve having an annular ring chamber at an outlet of the valve.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-02 | 1985-05-04 | 1985-11-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-02 | 1989-05-04 | 1989-11-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-02 | 1993-05-04 | 1993-11-03 | $7700.00 | Window Closed / Lapsed |